Since the late 1990s, there has been an explosion in the use of club drugs among men who have sex with men (MSM) and young adults, which includes cocaine, MDMA (ecstasy), methamphetamine, ketamine, and GHB, among others (NIDA, 2001). These drugs pose an immediate and severe threat to the health and well-being of gay and bisexual men, particularly in urban areas. The health risks associated with these drugs stem from two sources: the physical and psychological risks that are associated with the use of club drugs, and the risk of HIV infection or transmission through unsafe sexual behavior while under the influence. Research shows that MSM are reporting more sexual risk behavior than in previous years and there is significant concern that HIV infection rates may once again be on the rise after more than a decade of remaining relatively stable. Currently there are no evidence-based interventions available that address club drug abuse and HIV sexual risk behaviors. We propose a theory-based brief intervention, based on the principles of Motivational Interviewing (MI) designed to reduce unsafe sexual practices and club drug use among HIV seropositive and seronegative men who have sex with men (MSM) who use club drugs. The objectives of the project are to: (1) recruit and enroll an ethnically diverse sample of 240 MSM; (2) test the efficacy of a brief MI intervention compared to a video-based educational control intervention; (3) test whether baseline quantity/frequency of club drug use and unprotected sex, psychiatric severity, motivation, and self-efficacy are significant predictors of change over time, and (4) test the cognitive mediators that are hypothesized to be fundamental to MI. Participants will be randomized into either an MI condition or an attention control condition that will consist of viewing videotapes. Participants will complete an intake assessment, and follow-up assessments at 3, 6, 9, and 12-months in order to assess short-term and longer-term effects. Biological markers will include urine testing for club drug and other drug use and HIV antibody testing will be utilized to confirm self-report data. Participants will be recruited through active and passive recruitment strategies from a variety of community-based venues in New York City.